DESCRIPTION (From the Applicant?s Abstract): A novel mouse model of retinal degeneration, the 5A11/Basigin null mouse, has recently been characterized by this laboratory and others. 5A11/Basigin is a membrane glycoprotein expressed on the apical and basal surfaces of the retinal pigmented epithelium, Muller glial cells, and photoreceptor cells (cell body and inner segments) of the mouse retina. Inactivation of the mouse 5A11/Basigin gene results in abnormal maturation of photoreceptor outer segments that precedes the eventual degeneration of photoreceptors, with a complete loss of inner and outer segments. Understanding the molecular mechanisms through which this specific degeneration occurs will undoubtedly lead to insights relevant to the clinical treatment of retinal dystrophies, the major cause of blindness in the Western world. Therefore, the studies proposed herein are aimed at investigating the molecular diversity of 5A11/Basigin gene expression during mouse retinal development as a path to understanding the function of this molecule.